The field of the invention generally relates to refrigerators, and more particularly relates to duct apparatus that conveys cold air from the freezer compartment through foamed-in-place insulation to a storage chamber within the fresh food compartment.
As is well known, most domestic refrigerators are insulated using a so-called foam-in-place process. In such process, a plastic liner is positioned in spaced relationship within an outer metal shell. Then, foam insulation is injected under pressure into the space between the liner and the shell, and the foam flows along the bottom, sides, and top of the liner filling all voids in the space. Subsequently, the foam solidifies and becomes a layer of rigid insulation surrounding the liner.
In the case of a side-by-side refrigerator, a freezer liner is generally positioned on one side and a fresh food liner is positioned on the other side. The two liners are spaced from each other so that the foam flows into the region therebetween forming a vertical partition. Typically, an evaporator chamber is formed within the freezer liner and a single fan is used to circulate air from the freezer and fresh food compartments over the evaporator and back to the respective compartments. The evaporator is activated and the air is proportioned so that the freezer compartment is generally maintained at approximately 0.degree. F. while the fresh food compartment is approximately 40.degree. F.
It is also well known that it is desirable to maintain certain foods at a temperature that is lower than the fresh food compartment. For example, it may be desirable to store meat or beverages at a temperature in the range of 32.degree. F.-35.degree. F. which is intermediate to the temperatures of the freezer and the fresh food compartments. For this purpose, many refrigerators have a meat keeper storage drawer, and some also have a beverage or quick chill storage chamber which typically is located within the door of the fresh food compartment.
U S. Pat. No. 4,586,347 discloses a side-by-side refrigerator having an intermediate temperature (e.g. 28.degree.-32.degree. F.) chamber within the fresh food compartment door. A port or passage is provided directly through the vertical partition between freezer and fresh food compartments, and the respective pressures are maintained so that cold air flows from the freezer compartment laterally through the passage in the partition to the storage chamber in the fresh food compartment door. However, with a wide range of freezer and fresh food compartment operating conditions such as the size and quantity of stored food, the pressures in the respective compartments may tend to be variable. Therefore, with such arrangement, it may be difficult to regulate the temperature within the storage chamber.
It would be desirable to provide a generally front-to-back duct to convey cold air directly from the evaporator chamber in the rear of the freezer liner to an intermediate temperature storage chamber within the fresh food compartment. With such arrangement, the pressure differential between the cold air source and the storage chamber would be relatively constant when the fan is operating, so the air flow rate could be accurately controlled. However, freezer and fresh food liners may not be precisely positioned within the shell so there may be a dimensional tolerance between the respective liner apertures through which the cold air is conveyed. Thus, it may be difficult to align the inlet and outlet ports of a duct to the respective liner cold air conveying apertures. The task is further complicated because the connections or joints of the duct to the respective liner apertures must be suitably sealed so that foam under pressure does not leak through the joints during the foam-in-place process.